1. Field of the Invention
The present invention relates to a display, and more particularly, to a three-dimensional display (3D-display).
2. Description of Related Art
Current three-dimensional (3D) display techniques are mainly classified into a stereoscopic type and an auto-stereoscopic type. The auto-stereoscopic type technique can be achieved by applying a holography method, a volumetric method, a multi-plane method, and a spatial-multiplexed method, etc. However, all the above methods have disadvantages. For example, a massive amount of data must be processed when the holography method is conducted, and the volumetric method or the multi-plane method is constrained by machine size and the space.
In a conventional spatial-multiplexed 3D display technique, barriers or lenses are disposed in front of a display panel to project images to different positions, such that a left eye and a right eye of a viewer is able to receive images at different angles, respectively. Further, the images received by the left-eye and the right-eye of the viewer are merged in the brain of the viewer, such that a 3D image is perceived.
FIG. 1 is a schematic diagram of a conventional 3D-liquid crystal display (3D-LCD). Referring to FIG. 1, the LCD 100 includes a plurality of parallax barriers 120 disposed in front of pixel units 110 for blocking light emitted from certain angles. Thus, the left and right eyes of the viewer respectively observe different pixel units 110, and accordingly the 3D image is perceived.
However, since the parallax barriers 120 of the LCD 100 block most of the light, the brightness of the 3D image is decreased.
Besides, the parallax barriers 120 separate the 3D image into the images respectively received by the left and right eyes. Thus, even though the LCD 100 is able to display the 3D image, resolution of the image displayed on the LCD 100 is reduced.
More particularly, the image resolution is reduced by half when the viewer closes his or her left or right eye.
Furthermore, since only two images are respectively provided for the left eye and the right eye, the viewer needs to be at a proper distance and position so as to perceive the corresponding 3D image, such that the choices of the viewing position are limited.
FIG. 2 is a schematic diagram of another conventional 3D-LCD. Referring to FIG. 2, the LCD 200 includes a first substrate 210 and a second substrate 220.
Curved lenses 230 of the 3D-LCD 200 are fabricated on the second substrate 220, and each of the curved lenses 230 is disposed corresponding to one pixel unit 240, such that the curved lenses 230 are able to control a refraction angle of light which passes through the corresponding pixel unit 240.
Thus, both eyes of the viewer receive different images generated by different pixel units 240, and accordingly the 3D image is perceived.
In addition, since the curved lenses 230 refract the images generated by the pixel units 240 to be at different angles, as long as the left eye and the right eye of the viewer respectively receive two of the images projected at different angles, the 3D image is perceived. Thus, in comparison with the LCD 100 as shown in FIG. 1, the LCD 200 allows the viewer to receive the 3D image at more view angles.
That is to say, the viewer is able to view different 3D images from different directions.
It should be noted that, if the LCD 200 displays a single 3D image with different view angles under a fixed resolution, the resolution of the 3D image provided by the LCD 200 is significantly decreased compared with the LCD 100 which provides a single view angle.
In addition, the curved lenses 230 are fabricated on the second substrate 220, and each of the curved lenses 230 must be disposed corresponding to one of the pixel units 240. Therefore, high alignment accuracy is required during fabrication, such that each of the curved lenses 230 disposed on a proper location for controlling the light emitting angle can be guaranteed. Furthermore, since fabrication of the curved lenses 230 is rather difficult, and each of the curved lenses 230 can be barely aligned to one of the pixel units 240 accurately, fabrication costs of the 3D-LCD 200 are hardly reduced.
U.S. Pat. No. 6,064,424 provides a 3D-LCD similar to the LCD 200 depicted in FIG. 2, in which a slanted lenticular element (equivalent to the curved lenses 230 as shown in FIG. 2) is used to project light of each of pixel units (equivalent to the pixel units 240 in FIG. 2) at different directions, such that the left and the right eyes of the viewer are able to receive different images, and then the 3D image can be perceived.
Hence, the 3D-display disclosed in said US patent has unfavorable resolution as that of the LCD 200.
In the light of the above, the conventional spatial-multiplexed 3D display still has disadvantages, such as low resolution, insufficient brightness, small view angles, image crosstalk, and so on.